Résumé : BACKGROUND
Quorum sensing (QS) could regulate gene expression so as to mediate some bacterial behaviors such as the production of extracellular polymeric substances (EPS) and biofilm formation. In this study, a quorum quenching (QQ) bacterium, was isolated from an indigenous lab-scale MBR and encapsulated in a dumpling-shaped microbial bag for biofouling control.
This QQ bacteria has a higher genetic homology with Acinetobacter bereziniae strain. The effect of time and temperature on the QQ activity of microbial bag was tested by degrading N-acyl homoserine lactone (AHL). The results showed the degradation of C8-HSL (N-Octanoyl-DL-homoserine lactone) and C6-HSL (N-Hexanoyl-L-homoserine lactone) could reach equilibrium within 2 h. In addition, the relatively suitable temperature for AHL degradation was 20°C, at which degradation rate of C6-HSL and C8-HSL by microbial bag was 88% and 69%, respectively. The antifouling efficiency of microbial bag was investigated by a constant pressure filtration system. With the microbial bag added, the decrease of permeability was obviously improved. After 14 d, the permeability with QQ decreased to 18% while the control experiment exhibited almost no permeability.
The excellent AHL degradation rate and the filtration test showed that this QQ bacteria has an excellent antifouling potential in membrane filtration systems.